The sun lets out lots of electromagnetic radiation. A chunk of this stuff is called visible light, this is what we can see. The least intense electromagnetic radiation we can see is red light and the most intense is blue light.

The UV in UVA, UVB, and UVC stands for Ultra Violet, it is more intense than violet light. It is also more damaging than visible light and that is why we need to protect our skin and eyes from it. Up to 80% of electromagnetic radiation can be reflected off the surface of the water. Surfers should protect themselves.

UVC Radiation

UVC radiation is the most powerful and would be extremely dangerous for humans, animals and plants, but fortunately it is blocked by what is left of the ozone layer. So we should stop messing that one up.

UVB Radiation

UVB radiation is the second most powerful. It is largely absorbed by the atmosphere too, but some still gets through. UVB rays are also blocked by normal window glass. It is more damaging to the eyes than UVA light, but there is less of it.

UVA Radiation

UVA radiation is very similar to visible light and makes up 98.7% of the UV radiation that hits the Earth's surface. UVA rays can pass through the cornea of the eye and be absorbed by the lens. This is the main cause of cataracts. If your natural lens has been removed some of the rays can pass through and hit the retina. Powerful rays hitting the retina is believed to be the main cause of macular degeneration.